This invention relates to a beacon, i.e., a lighting device that concentrates emitted light onto a horizontal plane, and which can be used as a marker or aviation obstruction beacon to help identify towers, tall building, smokestacks or the like that may rise to an elevation of one hundred fifty feet to several hundred feet and pose a hazard to aircraft navigation. The invention is more specifically directed to a beacon or light generator that efficiently directs light generally omni-directionally along a horizontal plane to form a horizontal disk of light, or a portion of a disk of light, within some small angle Theta (θ) from the horizontal. The invention also concerns construction of the beacon in which a ring light emitter or a ring of emitters, such as LEDs, are arranged between upper and lower reflectors of a generally parabolic profile, and with a collimating lens circling around the ring of emitters to direct the central portion of the light onto the horizontal plane, with the remaining light that is above or below the collimating lens being directed by the upper and lower reflectors onto the horizontal plane.
A need has long existed for a beacon that is efficient and reliable, and which can be easily installed on a tall building, smoke stack, tower, or other elevated structure, and which is of robust construction. A need has also long existed for a beacon with improved heat management for the lighting and for the electrical power drive circuits for the lighting.
A number of beacons have been proposed in which light-emitting diodes or LEDs are arranged to provide illumination, and with focusing reflectors, in the form of a conic section, that direct the light from the LEDs onto the horizontal plane. Other beacons are provided with a lens or prism of glass or clear plastic which focuses or collimates a central part of the illumination, and which redirects the remaining part of the light using total internal reflection within the prism. These arrangements are complex and expensive to construct, and do not conduct the heat away from the light emitting devices, thus limiting the power that can be applied to the beacon.